重金属在根际中的化学行为Ⅲ.土壤中铁形态转化的根际效应及其生态学意义  

Chemical behavior of heavy metals in rhizosphere Ⅲ. The rhizosphere effect of iron oxide transformation in soils and its ecological significance.

作　　者：王建林[1] 刘芷宇[1] 

机构地区：[1]中国科学院南京土壤研究所,南京210008

出　　处：《应用生态学报》1992年第4期339-345,共7页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金

摘　　要：本文研究了两种熟化水稻土和两种新垦红壤植稻后根际中铁的形态转化。结果表明,水稻土植稻后根际中无定形铁、游离铁、络合态铁及铁的活化度均低于非根际;红壤中除络合态铁的根际内外分布趋势与水稻土相同外,其余均与水稻土相反。穆斯堡尔谱特征表明,根际中氧化铁的四极矩分裂较大,内磁场较低,即根际中氧化铁被活化。差热分析结果表明根际土的持水力强于非根际土。这对根际微生态系统的生态环境保护、物质流的调控及水分的保持和有效利用有重要作用。The present paper deals with the characteristics of iron oxide transformation in rice rhizosphere and its ecological significance in two paddy soils and two red soils after growing rice (Oryza sativa L.) in rhizobox experiment.It was shown that the contents of Feo, Fed and Fee and the ratio of Feo/Fed were lower in rice rhizosphere grown in paddy soils, and the same was true for Fee content in red soils.However, the amounts of Fed and Feo and the ratio of Feo/Fed were higher in rice rhizosphere cultivated in red soils. The Mssbauer spectroscopic results indicated that Q.S. increased, while Hi decreased in rhizosphere soils as compared to nonrhizosphere soils.Meanwhile,the Fe(Ⅱ) was more in rice rhizosphere grown in paddy soils, and there existed a new iron oxide mineral,i.e.maghemite in the rhizosphere in one of red soils.These findings suggested that iron oxide in rhizosphere microecosystem were activated as the results of the rice root's physiological activity and exudation, microorganism's action on the root surface and in the rhizosphere. In addition, the results of DTA-TG revealed that the water retention capacity was higher in rhizosphere mieroecosYstem because of much more amorphous iron oxides and organic matter etc. in it. Rhizosphere effect of iron oxide transformation would affect: 1) adsorption and desorption of heavy metals and other pollutants; 2) bioavailability of soil iron oxides: 3) absorption of other nutrients such as P and Mn by crops: 4) matter flow and the effective use of water and nutrients in the rhizosphere microecosystem; and finally the ciop growth and quality of agricultural products.

关 键 词：铁形态转化 根际效应 重金属 

分 类 号：S154.4[农业科学—土壤学]